1. Field of the Invention
The present invention relates to power supplies and, particularly, to a small, lightweight, portable, rechargeable and modular integrated power source of the solar cell variety.
2. Description of the Prior Art
With the ever expanding use of the conventional battery in many types of equipment which rely on batteries for electrical power, the advantages of a portable, renewable, self-contained power source which is integrated within applications are self-evident, especially if during actual delivery of current the changing of depleted battery cells is eliminated. A power-on-demand capability, where maintenance can be held to a minimum, is extremely attractive when supplying power to emergency communication equipment. Never having to replace batteries, for example, in walkie-talkie radios, modular cellular telephones, pagers, radios, data recording devices and other hand-held portable equipment, offers money-saving operations and consequently a lower cost. With the advent of environmentally friendly, form malleable polymer battery, technology now exists to design and develop self-contained, energy-renewable power sources for all types of portable applications.
One prior art power source battery is disclosed in U.S. Pat. No. 3,005,862 wherein a solar battery can have its elements shaped or curved to desired configurations. In one embodiment, the solar panel itself can form a wall of a satellite. The preferred material of which the panelling is made is aluminum, although other materials such as stainless steel, beryllium, magnesium, or titanium, or even plastic may be reduced to its essential elements. U.S. Pat. No. ""862 merely demonstrates another way for mounting a solar battery.
U.S. Pat. No. 5,180,645 carries the principles of U.S. Pat. No. ""862 one step further by recognizing the importance of providing an integrated battery into or part of an equipment housing. U.S. Pat. No. ""645 is primarily directed, however, to a battery formed of first and second current collectors separated by a solid state electrolyte. FIG. 2 of U.S. Pat. No. ""645 shows such a battery embedded in a radio housing with the traditional role of the housing as a separate element intact.
In accordance with the invention of a self-contained, energy renewable power source, recent advances in technology have centered on the following achievements:
1. Improved performance and stability of polymer anode and cathode materials such as polypyrrole through improved electrolytic drying procedures and processing conditions.
2. Incorporated solid polymer electrolytes in prototype all-polymer batteries and modified solvents used in preparation of electrolytes such as polyacrylonitrile to achieve improved electrolyte performance.
3. Expanded class of solids used as polymer anodes and cathodes to include promising candidate materials including redox-couple substituted thiophenes to achieve higher cell potentials and stability.
The recent developments, moreover, in polymer batteries now provide a technology in which a battery can be integrated within the mechanical supporting structure for an application circuit. No longer will conventional restraints require a battery as a separate add-on component thereby dispensing with the need for a separate battery compartment and the cables historically necessary to connect the power source to the electronic components. The invention further considers the development of a novel and unique integration of a polymer battery coupled with miniaturized integrated electronics. With the ability to take on a shape malleable to a particular application, an environmentally friendly polymer battery can potentially incorporate solar cells, SRAMS, DRAMS and IC""s to provide power source and nonvolatile memory data collection and storage. In one preferred application, solar cells backed with a thin film polymer battery at the component level can supply a self-contained, lightweight, and fully integrated and energy renewable power source. Beyond the chip level, polymer batteries can be incorporated into devices as the mechanical backing and structures for multi-layer printed circuit board technology. In its most general sense, the nature of polymer battery technology is such that a chassis or housing can be molded into a desired shape using the battery material itself and still incorporate a power source for the intended application.
Many of the above advantages can also be obtained by combining the power management means of the invention with other types of batteries, e.g., lithium-ion, or with fuel cells such as hydrogen-oxygen or methane-oxygen.
The invention also comprises a method for assembling an integrated power source, the integrated power source comprising a rechargeable energy source, power management means and means for recharging the energy source, arranged in layers, the method comprising the steps of:
laminating the layers together to form a laminate structure such that external electrical interconnections are minimized; the laminate structure is resilient to vibration, shock, humidity and moisture; and thermal paths within the laminate structure are specified for thermal control; and
sealing the laminate structure within an hermetically sealed enclosure.
An additional step in the method of the invention comprises, before the laminating step, the step of inserting a layer of a structural composite between the other layers comprising the integrated power source.
Accordingly, an object of the invention is to assemble a polymer battery as the structural casing of an electronic unit so that interconnecting wires between the battery, a charging unit, and a regulating circuit are eliminated.
Another object of the invention is a power source consisting of solar cells, RF charging unit or microwave energy charging means which are integrated structurally with a polymer battery.
Yet another object of the invention is the integration of a polymer battery as the principal structural element in the formation of a solar-powered electronic unit.
A further object of the invention is an implementation for integrated power management electronics offering voltage regulation, under/over voltage control, under/over current control and polymer battery charging control utilizing polymer and other semiconductor circuitry.
Still another object of the invention is an integrated power source stacked on top of the integrated power management circuit layer which incorporate additional applications circuitry such as SRAM (static random access memory), DRAM""s (dynamic random access memory) for data storage purposes.
Yet another object of the invention is to laminate an integrated applications electronics layer onto the integrated power source thereby implementing miniaturization beyond the volumetric reduction gained by housing an applications board within an integrated power source enclosure.
Another object is a power source which combines on a layered p or n- doped polymer substrate resistive, capacitive components, semiconductors laminate layer on to another layer consisting of the solid polymer battery, all integrated onto a base material to provide a structural shell for an electronics unit.
Other objects and advantages of the invention will become apparent to those skilled in the art in the course of the following description.